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Date: Thu, 17 Nov 2022 21:33:56 +0100 From: Andrew Lunn <andrew@...n.ch> To: Gerhard Engleder <gerhard@...leder-embedded.com> Cc: netdev@...r.kernel.org, davem@...emloft.net, kuba@...nel.org, edumazet@...gle.com, pabeni@...hat.com Subject: Re: [PATCH net-next 1/4] tsnep: Throttle interrupts On Thu, Nov 17, 2022 at 09:14:37PM +0100, Gerhard Engleder wrote: > Without interrupt throttling, iperf server mode generates a CPU load of > 100% (A53 1.2GHz). Also the throughput suffers with less than 900Mbit/s > on a 1Gbit/s link. The reason is a high interrupt load with interrupts > every ~20us. Not my area of expertise, but is NAPI working correctly? It should be that you disable interrupts while NAPI is polling, and only re-enable interrupts when polling has stopped. If you are receiving at near line rate at 100% load, i would of thought that NAPI would be polling most of the time and interrupts would be mostly disabled? Interrupt coalescence makes a lot of sense thought, so the patch itself is useful. Andrew
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